Study on the effect of acid snow and rain on the ecosystem and structure

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Evaluation of Acidified Soils in Terms of pH and Dissolved ElementsThe influence of acid rain on soils has not been largely recognized in Japan, though the pH of the rain and snow falling in Niigata Prefecture has been found to be 4.6 on average. Since most of the rain and snow in this area is considered 'acidic', it must have an effect on the area's soils. In this study, the present state of soils gathered from mainly Niigata Prefecture was examined by the measurement of pH and the chemical analysis of dissolved elements from the soils. Attention was paid to the degree of soils acidification, i. e., the degree in which acidification has proceeded. As a result of this experimental study, it was determined that soil had become slightly acidified, and aluminum and manganese, which effect tree roots, dissolve only slightly out of non-acidified soils, while they dissolve easily out of acidified soils.Elution Phenomena of Acidic Ions from Granular Snow and Spherical IceIn the field of freez … More e separation, there have been few studies regarding the separation of solutes by forming ice spheres from the solution and melting them. In order to enhance the elution of sulfate ions from ice, spheres formed of sulfate-containing water were examined, and melting experiments were performed. First, ice spheres containing sulfate ions were packed in a column and melted, the concentration of sulfate ions in the drained effluent was then measured. The ice spheres were formed using two different methods. In the first method, a plastic mold having spherical holes of 18.0 mm diameter was used. The mold was refrigerated for 12 h in order to form spherical ice crystals. The other method involved the formation of falling droplets of the solution through a refrigerant controlled at about -30℃ and rapidly freezing them. The ice spheres formed in this way had an average diameter of 3.5 mm. Second, the ice spheres including sulfate were melted from the surface to the center in a glass vessel filled with an organic solvent and the change in the concentration of sulfate due to the melting was measured and the sulfate distribution in the sphere was estimated. In this experiment, the ice spheres having a diameter of 18.0 mm were melted. Less